134 
Psyche 
[Sept. 
species nantuckensis have a minimum ratio of 3 : 1 and 
may be over 7 : 1. This difference in proportions is very 
characteristic and accounts for a marked difference in the 
appearance of the saltmarsh* egg masses. They are no 
wider than the supporting grass blade while those of 
atratus may be twice as wide. There may be a possible 
connection between the more uniform exposure of the eggs 
in these thinner, extended masses and the temperature 
conditions of the coastal marshes. Nantuckensis egg 
masses vary at least from 15-35 mm. in length. However, 
they are very regularly only 4-5 mm. wide which is nearly 
the width of the Spartina blade. Generally they are laid 
in 2-3 well defined layers and at the highest point the mass 
will measure only 3-4 mm. Study of the figure will reveal 
that it is a photograph of a double egg mass. Horseflies 
not uncommonly add their eggs to previously deposited 
masses. However, the circumstances were somewhat un- 
usual in this case. 
About noon on August 22nd a restless female was seen 
flying from plant to plant along the border of the roadside 
ponds at Pine Island. She was apparently selecting an 
egg site, as subsequent events proved. After stalking her 
for several minutes, I succeeded in capturing her and put 
her in a small jar with a blade of grass bearing an egg 
mass that I had found shortly before. When I reached 
camp half an hour later she was already busily ovipositing 
directly over the older mass and continued without inter- 
ruption until 2 : 05 p.m. She probably started to lay 
between 12 : 30 and 12 : 45 and, therefore, was so engaged 
for nearly an hour and a half. As the photograph clearly 
shows, she neatly arranged her eggs over the older mass. 
The picture was taken at 4 :30 p.m. on August 23rd when 
the fresher eggs were about 27 hours old. The older ones 
beneath had hatched in mass early that morning. 
The ovipositing behavior of two other females was suf- 
ficiently aberrant to mention. When discovered one had 
laid about three quarters of her eggs and the second had 
deposited about a third of hers. Those of the first were 
in three small discreet clusters on the same grass blade. 
She was put into a pint container with her eggs and while 
